Fluorination of acyclic olefinic compounds



Patented Mar. 16, 1948 um'rao sures PATENT orncs FLUORINATION OI"AOYOLIC OLEFINIC COMPOUNDS Anthony F. Banning. Woodstown, N. 1., andJoseph D. Part, Wilmington, DeL, allignors to E. L du Pont de Nemonrs aCom any, Wil- Del., a corporation of IRE No Drawing. Application July12, 1946,

, Serial No. seam 20 Claims. (01. zoo-ass) able compounds. For example,they will not, in

general, produce the type of compound which would be producedtheoretically by the addition of two fluorine atoms at the double bondof an oleflnic compound. No satisfactory method has been knownheretofore for the addition of two fluorine atoms to a double bond of anacyclic oleflnic compound.

It is an object of the present invention to provide a method for thepreparation of orzanic fluorine compounds by the addition of twofluorine atoms to a double bond of an acyclic oleflnic compound. Anotherobject is to provide such a method whereby compounds. not readilyobtainable by methods known heretofore, may be readily obtained insubstantial yields. A further object is to provide a method for thepreparation of CFaCClFCChF. A still further object is to provide a noveland improved method for making CClzFCChF. Other objects are to advancethe art. Still other objects will appear hereinafter.

The above and other objects may be accomplished in accordance with ourinvention which comprises reacting an oleflnic compound with hydrogenfluoride and a metal oxide of the group of C020: and MnOz in a closedreaction vessel under conditions such that two atoms of fluorine areadded to the double .bond of the oleflnic compound. We have found that,if an acyclic oleflnic compound. which consists oi carbon and at leastone of the members of the group consisting of hydrogen, chlorine,bromine and fluorine, is

mixed with HF and one of C020: and MnOs at,

CI'BCCIFCChF 2 in substantial yields from CF:CCl=CCla. Also, by thismethod, we are able to readily prepare 5 in substantial yields withoutadmixture with its isomer. Still other compounds. obtainable withdifliculty heretofore, maybe readily prepared by .this method.

The acyclic oleflnic compounds, which may be treated in accordance without invention, are those which consist of carbon and at least one ofthemembers of the group consisting of hydrogen, chlorine, bromineandfluorine, that is, they are oleflnes, chloro oleflnes, chloro fluorooleilnes, fluoro oieflnes, bromo olefines, bromo-fluoro olefines,bromo-chloro oleflnes and bromo-chlorofluoro olefines. Such terms areemployed in their ordinarily understood sense. oiefln consists of carbonand hydrogen and congo tains one or more double bonds, 9. chloro oleflneis an oleflne in which at least one hydrogen atom has been substitutedby chlorine solely and a chioro-fluoro oleflne is an oleflne in which atleast one hydrogen atom has been replaced by as chlorine and at leastone other hydrogen atom which all of the hydrogens of the oleflne havebeen replaced by the halogen. The following are representative of theoleflnic compounds which may be treated in accordance with ourinvention:

The oleflnic compound will be mixed with the metal oxide in theproportion of at least 0.5 mole oi the oleflnic compound for each mole'of the metal oxide. Generally. there will be from about 1 to about 4moles of the oleflnic compound to each mole of the metal oxide andpreferably in the ratio of about2 to 1. Large excesses of the oleflniccompound may be used, but without advantage.

The hydrogen fluoride will generally be used in the proportion of atleast 5 moles to each mole of the metal oxide. Proportions of from about5 For exam ple, an

a g, a a.

3 moles to about 80 moles of HF for each mole of metal oxide have beenemployed with satisfactory results. Still larger excesses of HF may beemployed, if desired. Preferably, however, there will be employed fromabout 10 to about 20 moles of HF for each mole of metal oxide.

The reaction is exothermic, but is quite slow at temperatures below C.In the absence of cooling sufllcient to dissipate the heat as fast as itis generated, the mixture will slowly warm up with acceleration of thereaction until, at a temperature above 0. (2., the reaction becomesquite vigorous. rapidly generating large amounts of heat. Thetemperature. at which the vigorous exothermic reaction takes place, willdepend upon the particular oleilnic compound employed and the size andshape of the charge and of the reaction vessel. Generally. however, suchtemperature is between C. and 100 C. and usually between 5 C. and 60 C.

we have found that. in order to successfully carry out the reaction withthe production of substantial yields of the desired compounds, the metaloxide. hydrogen fluoride and oleflnic material should be mixed togetherin the desired proportions at a temperature below 0 C. and the reactioncarried out in a closed reaction vessel.

Preferably, the reactants are mixed at a temperature below --14 0. andparticularly at a temperature of from about 15 C. to about -'18 C., soas to provide a margin of safety for the closing of the vessel beforethe vigorous reaction starts.

The reaction vessel should be one which will withstand high pressures,as high autogenous pressures are generated due to the high temperaturesproduced and the volatility of the reactants. The reaction vessel may beconstructed of any metal which does not readily react with fluorine orhydrogen fluoride. Suitable metals are silver, nickel, Inconel. platinumand iron. The body of the vessel may be made of other metals and linedwith the non-reactive metal. The vessel will usually be provided withmeans for agitation and a reflux column. Usually. the reaction vesselwill be provided with means for cooling to the desired temperature formixing so that the ingredients may be mixed directly in the reactionvessel.

After the ingredients are mixed and the vessel is closed. thetemperature of the mixture is caused to rise above 0 C. to that at whichthe reaction proceeds rapidly. This may be accomplished by removing thecooling from the vessel and allowing the heat. generated by thereaction, to slowly raise the temperature the desired amount. Ifdesired, the rise in temperature may be assisted by applying heat to thevessel. Due to the heat generated in the reaction, the temperature oithe mixture at the completion of the vigorous reaction will besubstantially higher than that at which the vigorous reaction starts. Itwill usually be desirable to maintain the mixture at or above suchtemperature for a substantial period of time so as to complete thereaction as far as possible. Preferably, after the vigorous reaction hassubsided, the mixture is heated up to about 200 C. and maintained atthat point for several hours so as to insure completion of the reaction.

The reaction products, consisting essentially of excess H1", fluorinatedorganic material, unreacted olefin and metal compounds, may be treatedby various methods to separate and recover the valuable ingredients. Theorganic material and H F may be distilled out of the autoclave and thensubjected to anhydrous fractional distillation to separate substantiallyanhydrous H! from the organic material. Alternatively, the orBanicmaterial and H2! may be distilled out of the reaction vessel and passeddirectly through scrubbers to remove acidic constituents. followed bycollection of the acid-free organic material in vessels cooled to theappropriate temperatures. The organic material may then be subjected tofractional distillation. The organic constituents may be separated fromeach other and from 1-11" by fractional condensation. The metalcompounds may be discarded or subjected to hydrolysis and dehydration toobtain metal oxides for reuse in the proc- S.

In order to more clearly illustrate our invention preferred modes ofcarrying thmame into effect and the advantageous results to be obtainedthereby, the following examples are given:

Example I Into a steel autoclave, cooled to carbon-ice acetonetemperature, about -78 0., were charged one mole of tetrachloroethylene.one mole cobaltic oxide (C0103) and seven mole of anhydrous hydrogenfluoride. The reaction mixture was allowed to come to room temperatureand then digested at 200 C. for six hours with agitation. After coolingto 30 C., the pressure was released and the reaction mass drowned in icewater and steam distilled. The resulting organic layer was separated,dried over calcined calcium sulfate and fractionated. Fractionationyielded 0.32 mole of CFCla-CFC]: with the following constants: B. P.92.8 C. at 760 mm. of Hg; M. P. 265 0.; n -=1.41l5. As by-products. thecompounds CHCla-CClaF and CClzF-CCIF: were obtained.

Example 11 One mole of CC12=CC1CF3 was placed in a steel autoclave(cooled to carbon-ice acetone temperature, about -78 C.) with 0.54 moleof manganese dioxide (M1102) and 10 moles of anhydrous hydrogenfluoride. After warming up to room temperature. the autoclave was heatedat 200 C. for six hours with agitation. The reaction vessel was thencooled to 30 0., the pressure released and the reaction mass passedthrough water, then through calcined CaSO4 and condensed. Thiscondensate was then subjected to fractionation. About 0.2 mole ofCFsCClFCChF with the boiling range of 73 to 735 C. at mm. of Hg wasobtained. The major portion of the recovered material was unreactedstarting material I CFsCCl=CC12 Earample III A reaction with 1 mole ofCHCl=CCh, 0.4 mole of MnOz and 8 moles of HF was carried out underconditions similar to that described in Example 11. About 0.1 mole ofCHCIFCClzF, boiling at 12- 73 0., was isolated and identified.By-product CHClzCHCIF was also identified.

It will be understood that the preceding examples are given forillustrative purposes solely and we do not intend to restrict ourinvention to the specific embodiments disclosed therein. but intend tocover our invention broadly as in the appended claims. Many variationsand modifications may be made in the process without departing from thespirit or scope of our invention. For example, other acyclic oleflniccompounds may be empgyed in place of those specifically mention stepprocess, not known Metal oxides, in general. are not eflective in thisprocess and it could not be predicted which metal oxides would producethe desired results. For example, attempts to obtain the symmetricaladdition of fluorine to oleflns. such as CFCC1=CCI:, CCh=CCls andCHI=CHCL by employing in the process other metal oxides, such as NizOs,T: and SbrOs. were unsuccessful.

This invention provides a novel method for preparing organic fluorinecompounds. It provides a method for the symmetrical addition of fluorineto oleflnic compounds, permitting the synthesis oi compounds heretoforediiflcult and tedious or impossible to prepare. For example, it providesa new and more efllcient method for the preparation of CClaFCChF. Priorto our invention, CClaFCChF was obtained with difflculty as anintermediate in the preparation of CClFrCClrF from CzCie and antimonyfluorides and then in very small yields admixed with the isomerCClFzCCh. By our process, two fluorines are symmetrically added toCC12=CC12 with the formation of CChFCClaF without admixture with theisomer. Also, by our method, CFsCClFCChF is readily obtained fromCF3CC1=CC12.

The products of the reaction are useful for various commercial purposes.They may be used as refrigerants and as intermediates for thepreparation of fluorine-containing olefines and perfluorinated oleflnes,useful in the production of fluoro polymers and interpoiymers. Thecompounds, produced by our method, may also be used as solvents andreaction media. Furthermore, by our invention, we have provided a methodwhereby two fluorine atoms are added to oleflnic compounds by aneconomical oneor used heretofore.

We claim:

1. The process of adding fluorine to a double bond of an acyclicolefinic compound which consists of carbon and at least one of themembers of the group consisting of hydrogen, chlorine, bromine andfluorine which comprises mixing, in a reaction vessel at a temperaturebelow 0 C., at least 0.5 mole of the olefinic compound and at least 5moles of HF with one mole of a member of the group consisting of C020:and MnOs, closing the reaction vessel, causing the temperature to riseabove 0 C. to that at which the reaction proceeds rapidly, maintainingthe mixture at at least the latter temperature until the reaction iscomplete and then separating the products.

2. The process of adding fluorine to a double bond of an acyclicolefinic compound which consists of carbon and at least one or themembers of the group consisting of hydrogen, chlorine, bromine andfluorine which comprises mixing, in a reaction vessel at a temperaturebelow-14 C., at least 0.5 mole of the oleflnlc compound and at least 5moles of HIE with one mole of a member of the group consisting of C020:and Mp0s, closing the reaction vessel, causing the temperature to riseabove 0 C. to that at which the reaction proceeds rapidly, maintainingthe mixture at at least the latter temperature until the reaction iscomplete and then separating the products.

3. The process of adding fluorine to a double bond of an acyclicoleflnic compound which consists of carbon and at least one of themembers of the group consisting of hydrogen, chlorine, bromine andfluorine which comprises mixing, in a reaction vessel at a temperaturebelow 0 0., at least 0.5 mole of the oleflnic compound and from about 5to about 30 moles oi HI" with one mole or a member of the groupconsisting of 00:0: and MnOa, closing the reaction vessel, causing thetemperature to rise above 0' C. to that at which the reaction proceedsrapl maintaining the mixture at at least the latter temperature untilthe reaction is complete and then separating the products.

4. The process of adding fluorine to a double bond 01' an acyclicoleflnic compound which consists of carbon and at least one of themembers of the group consisting of hydrogen, chlorine, bromine andfluorine which comprises mixing, in a reaction vessel at a temperaturebelow l4'' 0., from about 1 to about 4 moles of the oleflnic compoundand from about 5 to about 30 moles oi HF with one mole of a member oithe group consisting of 00:0: and MnOz, closing the reaction vessel,causing the temperature to rise above 0. C. to that at which thereaction proceeds rapidly, maintaining the mixture at at least thelatter temperature until the reaction is complete and then separatingthe products.

5. The process oi adding fluorine to a double bond of an acyclicoleflnic compound which consists of carbon and at least one of themembers of the group consisting of hydrogen, chlorine, bromine andfluorine which comprises mixing, in a reaction vessel at a temperatureof from about 15 C. to about -78 C., from about 1 to about 4 moles ofthe olefinic compound and from about 10 to about 20 moles of HF with onemole of a member of the group consisting of C020: and M1102, closing thereaction vessel, causing the temperature to rise to a temperature offrom 0 C. to about 200 C. at which the reaction proceeds rapidly,maintaining the mixture at at least the latter temperature until thereaction is complete and then separating the products.

6. The process of adding fluorine to a double bond of an acyclicchloro-fiuoro olefin which comprises mixing, in a reaction vessel at atemperature below 0 C., at least 0.5 mole of the olefin and at least 5moles of HF with one mole of a member of the group consisting 0! C020:and MnOz, closing the reaction vessel, causing the temperature to riseabove 0 C. to that at which the reaction proceeds rapidly, maintainingthe mixture at at least the latter temperature until the reaction iscomplete and then separating the products.

7. The process of adding fluorine to a double bond of an acyclicchloro-fluoro olefin which consists of carbon, chlorine and fluorinewhich comprises mixing, in a reaction vessel at a temperature below 14C., from about 1 to about 4 moles of the olefin and from about 5 toabout 30 moles of HF with one mole of a member of the group consistingof C020: and Minor, closing the reaction vessel, causing the temperatureto rise above 0 C. to that at which the reaction proceeds rapidly,maintaining the mixture at at least the latter temperature until thereaction is complete and then separating the products.

8. The process of adding fluorine to a double bond of an acyclicchloro-fluoro olefin which consists of carbon, chlorine and fluorinewhich comprises mixing, in a reaction vessel at a temperature of fromabout 15 C. to about -78 0., from about 1 to about 4 moles of the olefinand from about 10 to about 20 moles of HF with one mole of a member ofthe group consisting of C020: and MnOa, closing the reaction vessel,causing the temperature to rise to a temperature of from 0 C. to about200 C. at which the reaction proceeds rapidly. maintaining themixtemperature until the separating the 7 ture at at least the latterreaction is complete and then CFsCCl=CCh which comprises mixing in areaction vessel at a temperature oi from about 15 C. to about 'l8 C.,from about 1 to about 2 moles of the CF3CC1=CC12 and from about 10 toabout 20 moles of HF with one mole of a member of the group consistingof C020: and MnOa, closing the reaction vessel, causing the temperatureto rise to a temperature of from C. to about 200 C. at which thereaction proceeds rapidly, maintaining the mixture at at least thelatter temperature until the reaction is complete and then separatingthe CF'aCClFC-ClaF from the reaction mixture.

11. The process of adding fluorine to a double bond of an acyclic chloroolefin which comprises mixing, in a reaction vessel at a temperaturebelow 0 C., at least 0.5 mole of the olefin and at least 5 moles of HFwith one mole of a member of the group consisting of C020: and Minor,closing the reaction vessel, causing the temperature to rise above 0 C.to that at which the reaction proceeds rapidly, maintaining the mixtureat at least the latter temperature until the reaction is complete andthen separating the products.

12. The process of adding fluorine to a double bond of an acyclic chloroolefin consisting of carbon and chlorine which comprises mixing. in areaction vessel at a temperature below 0C., at least 0.5 mole of theolefin and at least 5 moles of HF with one mole of a member of the groupconsisting of C020: and M1102, closing the reaction vessel, causing thetemperature to rise above 0 C. to that at which the reaction proceedsrapidly, maintaining the mixture at at least the latter temperatureuntil the reaction is complete and then separating the products.

13. The process of adding fluorine to a double bond of an acyclic chloroolefin consisting of carbon and chlorine which comprises mixing, in areaction vessel at a temperature of from about -15 C. to about -78 C.,from about 1 to about 4 moles of the olefin and from about to about 20moles of HF with one mole of a member of the group consisting of C010:and Minor, closing the reaction vessel, causing the temperature to riseto a temperature 01 from 0 C. to about 200 C. at which the reactionproceeds rapidly, maintaining the mixture at at least the lattertemperature until the reaction is complete and then separating theproducts.

14. The process of making CClsFCChF by adding fluorine to the doublebond of CCla==CCla which comprises mixing, in a reaction vessel at thebelow 0 0.. at least 0.5 mole of and at least 5 moles of H! with onemole or a member of the group consisting of C020: and MnOa. closing thereaction vessel, causing the temperature to rise above 0 C. to that atwhich the reaction proceeds rapidly. maintaining the mixture at at leastthe latter temperature until the reaction is complete and thenseparating the CW .irom the reaction mixture.

15. The process of making CChFCChF by adding fluorine to the double bondof CCla==CCla which comprises mixing, in a reaction vessel at atemperature 01' trom about 15 C. to about -78 0., irom about 1 to about2 moles or the CCl===CClz and from about 10 to about 20 moles of HF withone mole of a member of the group consisting 0! C020: and MnOa, closingthe reaction vessel, causing the temperature to rise to a temperature offrom 0 C. to about 200 C. at which the reaction proceeds rapidly,maintaining the mixture at at least the latter temperature until thereaction is complete and then separating the CClaFCClzF from thereaction mixture.

16. The process or adding fluorine to a double bond of an acyclicolefinic compound which consists of carbon and at least one of themembers of the group consisting of hydrogen, chlorine, bromine andfluorine which comprises mixing, in a reaction vessel at a temperatureof below 0 C., at least 0.5 mole of the olefinic compound and at least 5moles of HF with one mole of MllOz, closing the reaction vessel, causingthe temperature to rise above 0 C. to that at which the reactionproceeds rapidly, maintaining the mixture at at least the lattertemperature until the reaction is complete and then separating theproducts.

1'7. The process of adding fluorine to a double bond 01 an acyclicchloro-fluoro olefin which comprises mixing, in a reaction vessel at atemperature below 0 C., at least 0.5 mole of the olefin and from about 5to about 30 moles of HF with one mole of M1102, closing the reactionvessel, causing the temperature to rise above 0 C. to that at which thereaction proceeds rapidly, maintaining the mixture at at least thelatter temperature until the reaction is complete and then separatingthe products.

18. The process of adding fluorine to a double bond of an acyclicchloro-fiuoro olefin which consists of carbon, chlorine and fluorinewhich comprises mixing, in a reaction vessel at a temperature of fromabout l5 to about -'l8 C.. from about 1 to about 4 moles oi the olefinand from about 10 to about 20 moles of HF with one mole of MnOa, closingthe reaction vessel, causing the temperature to rise to a temperature 0!from 0 C. to about 200 C. at which the reaction proceeds rapidly,maintaining the mixture at at least the latter temperature until thereaction is complete and then separating the products.

19. The process of making CFaCClFCClaF by adding fluorine to the doublebond of CFaCCl: CClz which comprises mixing, in a reaction vessel at atemperature below 0 C. at which the reaction proceeds slowly, at least0.5 mole of the and at least 5 moles oi HF with one mole of M1102,closing the reaction vessel, causing the temperature to rise above 0 C.to that at which a, temperature cCh=CCh CFaCCi=CC12 which comprisesmixing, in a reaction vessel at a temperature of from about 15 C. toabout 10 78 C., from about 1, to about 2 moles of the CFhCCi=CCh andfrom about 10 to about 20 moles of HF with one mole of M1102, closingthe reaction vessel, causing the temperature to rise to a temperature offrom 0 C. to about 200 C. 15 2,062,743

10 at which the reaction proceeds rapidly. maintaining the mixture at atleast the latter temperature until the reaction is complete and thenseparating the CFEiCClFCChF from the reaction 5 mixture.

ANTHONY F. BENNING. JOSEPH D. PARK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,437,993.

Number Name Date Daudt et a1. Dec. 1, 1936 March 16, 1948.

ANTHONY F. BENNING ET AL. It is hereby certified that errors appear inthe specification of the above numbered patent requiring correction asfollows:

lumn 2, line 10, for the word "out read our; column 5, line 6, ExampleIII, for OHl-CHC1" read OHOZ= CHOZ; column 7, line 16, claim 9, for nailread "until; and that the said Letters Patent should be read with th esecorrections therein that the same may conform to the record of the casein the Patent Ofice.

Signed and sealed this 11th day of May, A. D. 1948.

THOMAS F. MURPHY,

Assistant Uommkdoaero/ PM.

CFaCCi=CC12 which comprises mixing, in a reaction vessel at atemperature of from about 15 C. to about 10 78 C., from about 1, toabout 2 moles of the CFhCCi=CCh and from about 10 to about 20 moles ofHF with one mole of M1102, closing the reaction vessel, causing thetemperature to rise to a temperature of from 0 C. to about 200 C. 152,062,743

10 at which the reaction proceeds rapidly. maintaining the mixture at atleast the latter temperature until the reaction is complete and thenseparating the CFEiCClFCChF from the reaction 5 mixture.

ANTHONY F. BENNING. JOSEPH D. PARK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,437,993.

Number Name Date Daudt et a1. Dec. 1, 1936 March 16, 1948.

ANTHONY F. BENNING ET AL. It is hereby certified that errors appear inthe specification of the above numbered patent requiring correction asfollows:

lumn 2, line 10, for the word "out read our; column 5, line 6, ExampleIII, for OHl-CHC1" read OHOZ= CHOZ; column 7, line 16, claim 9, for nailread "until; and that the said Letters Patent should be read with th esecorrections therein that the same may conform to the record of the casein the Patent Ofice.

Signed and sealed this 11th day of May, A. D. 1948.

THOMAS F. MURPHY,

Assistant Uommkdoaero/ PM.

